Empress tree
Also known as
Princess tree, Foxglove tree, Royal paulownia, Kiri
Keep this plant’s care guide close at hand.
Get the appAbout Empress tree
Paulownia tomentosa is a fast-growing, deciduous tree native to China, renowned for its spring display of large, foxglove-like, lavender flowers that appear on bare wood before leaf-out. It typically reaches 10–20 m (33–66 ft) with a broad, open crown. Leaves are opposite, heart-shaped, and very large—often 15–30 cm, and much larger on coppiced shoots—with a velvety (tomentose) underside. Bark is thin, gray-brown, and lightly fissured. The woody capsules persist through winter and release vast numbers of winged seeds. It tolerates poor, compacted soils and urban pollution, establishing quickly on disturbed sites, but prefers well-drained, fertile substrates. Hardy in temperate climates, it withstands summer heat and, once established, moderate drought. In cultivation it is used for rapid shade, striking flowers, and for coppice to produce giant foliage; the lightweight, stable wood is valued in crafts. In many regions it self-seeds readily and can be invasive, so management and responsible placement are essential.
Taxonomy
Properties & Requirements
How to care for Empress tree
Water
Water deeply and regularly during the first 1–2 growing seasons to establish a robust root system: approximately 20–40 liters weekly, adjusting for rainfall and soil type. Allow the top 5–8 cm of soil to dry between waterings; avoid waterlogged conditions, which promote root problems. Once established, the tree is moderately drought tolerant and typically needs only supplemental watering during prolonged dry spells. Container-grown specimens dry faster; water when the top third of the potting mix is dry and ensure excellent drainage.
Light
Provide full sun for best flowering and form—minimum 6–8 hours of direct light daily. Light shade is tolerated, but growth becomes lankier and flower set declines. In densely shaded sites, leaves enlarge but branches can become brittle and prone to breakage. For containerized or nursery stock overwintered under cover, keep in the brightest possible exposure and, if indoors temporarily, supplement with strong grow lights to approximate full sun until outdoor conditions are suitable.
Nutrients
Paulownia tomentosa is not a heavy feeder once established. At planting, incorporate well-rotted compost into a well-drained soil. For young or container-grown trees, apply a balanced, slow‑release fertilizer (e.g., 10‑10‑10 or 14‑14‑14) in early spring at label rates. Avoid high nitrogen late in the season, which encourages tender growth susceptible to frost. On poor soils, a light supplemental feeding in midsummer is acceptable. Maintain soil pH near neutral to slightly acidic and ensure adequate micronutrients through organic matter rather than frequent soluble feeds.
Temperature
Hardy in USDA Zones 5–9. Established trees tolerate winter lows to around −23 to −15°C (−10 to 5°F), though flower buds and young shoots are vulnerable to late spring frosts. Optimal growth occurs between 18–30°C (65–86°F). Provide a wind-sheltered, sunlit position to minimize frost scorch and mechanical damage to large leaves. In very hot, arid climates, occasional heat scorch can occur; maintain soil moisture and use organic mulch to moderate root-zone temperatures.
